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July 22, 2012 [Issue 8408] New: Purity calculation should be improved | ||||
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http://d.puremagic.com/issues/show_bug.cgi?id=8408 Summary: Purity calculation should be improved Product: D Version: D2 Platform: All OS/Version: All Status: NEW Severity: normal Priority: P2 Component: DMD AssignedTo: nobody@puremagic.com ReportedBy: k.hara.pg@gmail.com --- Comment #0 from Kenji Hara <k.hara.pg@gmail.com> 2012-07-22 05:27:35 PDT --- If the argument values that given to a function marked as pure doesn't appear in its return value, then the function should become 'strong purity'. An example: int[] func(const(int)[] arr) pure; The parameter 'arr' refers const integers through its slice, but func returns int[], so func cannot return arr directly (without unsafe cast) and becomes 'strong purity' function. The parameter 'arr' refers const integers through its slice, but func returns int[]. const(int)[] is not implicitly convertible to int[], then func cannot return arr directly (without unsafe cast like cast(int[]) arr) and becomes 'strong purity' function. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
September 09, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 Kenji Hara <k.hara.pg@gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |pull --- Comment #1 from Kenji Hara <k.hara.pg@gmail.com> 2012-09-09 06:21:21 PDT --- https://github.com/D-Programming-Language/dmd/pull/1110 -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
September 09, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 bearophile_hugs@eml.cc changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |bearophile_hugs@eml.cc --- Comment #2 from bearophile_hugs@eml.cc 2012-09-09 07:03:15 PDT --- This rule makes more functions (tagged as pure) become strongly pure, this is positive. On the other hand for the programmer it's increasingly harder to know if a function is weak pure or strongly pure just looking at it. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
September 09, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #3 from Kenji Hara <k.hara.pg@gmail.com> 2012-09-09 07:24:46 PDT --- (In reply to comment #2) > This rule makes more functions (tagged as pure) become strongly pure, this is > positive. Thanks. But, I've been filed this as a part of issue 8409, so the pull request doesn't cover all cases. > On the other hand for the programmer it's increasingly harder to know if a function is weak pure or strongly pure just looking at it. I think it is not so difficult if you summarize it. - If the function can modify function argument through its parameters, it is weakly pure. - If the function arguments don't appear in the part of the returned value, or the returned value is not a part of arguments, then it is strongly pure. - Otherwise, it is constant pure. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
November 13, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #4 from bearophile_hugs@eml.cc 2012-11-12 20:23:55 PST --- *** Issue 9011 has been marked as a duplicate of this issue. *** -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
December 04, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #5 from github-bugzilla@puremagic.com 2012-12-03 22:00:20 PST --- Commits pushed to master at https://github.com/D-Programming-Language/dmd https://github.com/D-Programming-Language/dmd/commit/41c52a324d0526a079039041c64afc1d3983eb58 fix Issue 8408 - Purity calculation should be improved https://github.com/D-Programming-Language/dmd/commit/b6a809346a43c7fbf350bd4181d350dd9b2cd4e6 Merge pull request #1110 from 9rnsr/fix8408 Issue 8408 - Purity calculation should be improved -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
December 06, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #6 from bearophile_hugs@eml.cc 2012-12-05 17:36:09 PST --- Is it correct that x1 refused and x2 accepted? char[] foo1(int[] arr) pure { return new char[10]; } immutable(char)[] foo2(int[] arr) pure { return new char[10]; } void main(string[] args) { immutable x1 = foo1([1, 2]); // Error: cannot implicitly convert immutable x2 = foo2([1, 2]); // OK } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
December 07, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #7 from bearophile_hugs@eml.cc 2012-12-06 18:07:32 PST --- (In reply to comment #6) > Is it correct that x1 refused and x2 accepted? I guess I have to wait or Issue 8409 to be fixed before looking for possible troubles. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
December 07, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 --- Comment #8 from Kenji Hara <k.hara.pg@gmail.com> 2012-12-06 19:33:50 PST --- (In reply to comment #6) > Is it correct that x1 refused and x2 accepted? > > > char[] foo1(int[] arr) pure { > return new char[10]; > } > immutable(char)[] foo2(int[] arr) pure { > return new char[10]; > } > void main(string[] args) { > immutable x1 = foo1([1, 2]); // Error: cannot implicitly convert > immutable x2 = foo2([1, 2]); // OK > } I'm not sure that this should be allowed. foo1 can rewrite the elements referred from arr, then it is deduced to weak purity. In current principle, the returned value from weak purity function cannot be converted to immutable implicitly (it is only allowed for strong purity function). If you change the signature of foo1 to: char[] foo1(const int[] arr) pure; Then foo1 will be deduced to strong purity, and implicit conversion to immutable for initializing x1 will be succeeded. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
December 11, 2012 [Issue 8408] Purity calculation should be improved | ||||
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Posted in reply to Kenji Hara | http://d.puremagic.com/issues/show_bug.cgi?id=8408 Walter Bright <bugzilla@digitalmars.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED CC| |bugzilla@digitalmars.com Resolution| |FIXED -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- |
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